Wednesday, March 17, 2010

Love in the Time of Crinoids

As a kid, I dreamed of digging in my backyard or the sandbox at school and happening across a big honkin' dinosaur bone. The more I'd dig, the more dinosaur I'd find, until I had a dinosaur of my very own, and paleontologists from the Field Museum came by to see what I'd found. The local paper would print a picture of me. My popularity at school would skyrocket.

Then I learned that Northwest Indiana is somewhat less than a hotspot for Mesozoic fossils. Furthermore, there was so much asphalt and unconsolidated rock and soil laying around, finding fossils of any kind was rare (though there are occasional mammoth bones turned up by farmers). Luckily, this didn't squelch my interest in things ancient. I just got curious about geology and why, contrary to my fervent expectations, the ground everywhere wasn't teeming with dinosaur fossils.

When I was a teenager I finally saw the Smokies, the Rockies, the badlands of South Dakota, Yellowstone, and the Bonneville Salt Flats. Something about the exposed rock thrilled me. Heck, just driving a road cut into a hillside excited me (still does, actually). The problem was, I didn't have any exposed bedrock where I lived. Leaving Northwest Indiana became an inevitability at that point. I wanted to be somewhere that the real nitty gritty hardcore stuff the Earth is made of is easily accessible. I think that part of the excitement is that these places, where rock meets water and other weathering agents, are dynamic places where ecosystems are made.

Now my wife and I live in Bloomington, in south central Indiana, and it's lousy with interesting geology. The bedrock under my house is limestone created during the period called the Mississippian. This was the first half of the period more widely known as the Carboniferous, named for the great coal-bearing strata it contains. The coal is the compressed biomass of the swampy forests that were the dominant land ecosystem of Carboniferous Earth, a process that mainly took place during the second half of the period, called the Pennsylvanian. The Mississippian deposits underlying Bloomington are the remains of shallow seafloors, and then as now, shallow seas teemed with life.

Thanks to this, I've collected a small assortment of marine fossils, mostly fragments of sea lilies called crinoids, as well as a few brachiopods. Really, you could do a lot worse than the Carboniferous when picking a place to live. It's arguably the geological period with the deepest impact on our lives, offering up the coal on which the industrial revolution was run and limestone that went into building the Pentagon and the Empire State Building, among others. Any Indiana kid feeling left out of the dinosaur fossil jamboree of the Western US actually has plenty to be proud of.

Here are a couple photos of a some crinoid stem pieces I found last year. Get enough of them and you've got one handsome necklace.

Three Lakes Trail

Three Lakes Trail


  1. Nice fossils! I've dug up a few brachs in my time, a 65 million year old croc tooth, a worm fossilized burrowing into some wood, but no crinoids! Luckyyyy!

    But question: am I a bad person if I think brachiopods are boring?

  2. There are so many of them, they kind of become boring by sheer volume. And I think we all have critters we just don't find interesting. I find it difficult to get excited about fish, unless they're really outlandish like anglerfish. And most fish are a heck of a lot more charismatic then brachiopods!

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  4. I guess a fish fossil with a brachiopod fossil inside its stomach would redeem both... better yet, a brachiopod with a fish in its stomach. (I had to delete and re-post this comment because there was an unforgivable grammatical error- "it's" vs. "its")

  5. Thank you Boneyard! I just realized that I have a lot of "before my time" posts here at LITC to catch up on. I am thrilled.


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